A boat is a roundish sort of thing. Round is not an ideal hydrodynamic shape. Push it through the water and it will tend to wander, much like my prose, unless something is added to set things straight. The pull of oars is generally symmetrical but unless you are very good and well practiced your rowboat will respond to the inconsistencies in your stroke. You will constantly be making corrective moves that waste a lot of energy. Sometime after the first primitive boatbuilders decided to hollow out a log, instead of merely sitting astride, measures were taken to bring directional stability to meandering watercraft.
Boats built with a long deep keel have the solution built in. those that are shallow with uninterrupted bottoms require the addition of some appendage to bite into the medium through which it travels and provide resistance to turning moments. Like the feathers on an arrow a skeg gives the lateral resistance needed to create a straight track and a means by which the average Joe can cross great waters with efficiency and a sense of purpose. The skeg on some craft is the aftermost portion of an external keel.
I was hanging about Dave’s boat shed one Saturday afternoon when the project du jour was the affixing of the skeg to the Chester Yawl. Like many small plywood boats the Yawl does not have a structural keel. The bottom planks are reinforced with layers of fiberglass and epoxy on the inside and outside. The plywood skeg is attached along the center-line of the boat. It is about four feet long and runs from the transom forward until it tapers in a fair line with the rockered profile of the bottom of the hull. It’s bottom edge is capped with a wear strip made from Spanish Cedar.
The bottom planking comes together at an angle forming a ridge. By way of preparation for receiving the skeg the keel area needed to be planed and sanded down a bit to provide a flat landing area along the aftermost portion of the keel area. Dave applied a longboard with 80 grit sandpaper to the appropriate area. This effort was made keeping a profile that would match the curve of the skeg. It was a hand and and eye move with frequent trial fittings.
The installation of this part is neither rocket science or precision woodworking. Dave drilled the three required holes through the bottom of the boat along the centerline. The drill was run through the same holes again with the skeg in place to make pilot holes.We mixed up some thickened epoxy, mayonnaise consistency, and applied it to the mating surfaces of skeg and boat bottom. The skeg thus slathered was placed in position and screws were driven in from below. As excess epoxy squeezed out along the the joint we filleted it to make a neat transition. Later on fiberglass would be applied making a strong and useful appendage which will do much to make the Chester Yawl fly along her course, straight and true.